Linux: Use After Free
CVE-2024-35986 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.0 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 25b3498485ac281e5851700e33b97f12c9533fd8, 73224a5d2180066c7fe05b4656647601ba08d588, 9827caa5105fb16d1fae2e75c8d0e4662014b3ca as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.22% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 25b3498485ac281e5851700e33b97f12c9533fd8 or 73224a5d2180066c7fe05b4656647601ba08d588 or 9827caa5105fb16d1fae2e75c8d0e4662014b3ca or bf6e4ee5c43690e4c5a8a057bbcd4ff986bed052, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.90 or 6.6.30 or 6.8.9, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 48969a5623ed918713552e2b4f9d391c89b5e838 up to, but not including, 25b3498485ac281e5851700e33b97f12c9533fd8; 48969a5623ed918713552e2b4f9d391c89b5e838 up to, but not including, 73224a5d2180066c7fe05b4656647601ba08d588; 48969a5623ed918713552e2b4f9d391c89b5e838 up to, but not including, 9827caa5105fb16d1fae2e75c8d0e4662014b3ca; 48969a5623ed918713552e2b4f9d391c89b5e838 up to, but not including, bf6e4ee5c43690e4c5a8a057bbcd4ff986bed052; 5.18 | 25b3498485ac281e5851700e33b97f12c9533fd8, 73224a5d2180066c7fe05b4656647601ba08d588, 9827caa5105fb16d1fae2e75c8d0e4662014b3ca, bf6e4ee5c43690e4c5a8a057bbcd4ff986bed052 |
| Linux | Linux Kernel | 5.18 up to, but not including, 6.1.90; 6.2 up to, but not including, 6.6.30; 6.7 up to, but not including, 6.8.9; 6.9 | 6.1.90, 6.6.30, 6.8.9 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.0 | High | CNA |
| CVSS 3.1 | 5.5 | Medium | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: phy: ti: tusb1210: Resolve charger-det crash if charger psy is unregistered The power_supply frame-work is not really designed for there to be long living in kernel references to power_supply devices. Specifically unregistering a power_supply while some other code has a reference to it triggers a WARN in power_supply_unregister(): WARN_ON(atomic_dec_return(&psy->use_cnt)); Folllowed by the power_supply still getting removed and the backing data freed anyway, leaving the tusb1210 charger-detect code with a dangling reference, resulting in a crash the next time tusb1210_get_online() is called. Fix this by only holding the reference in tusb1210_get_online() freeing it at the end of the function. Note this still leaves a theoretical race window, but it avoids the issue when manually rmmod-ing the charger chip driver during development.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Use After Free vulnerabilities
- 7.8 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
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